1. Field of the Invention
The present invention generally relates to water detection systems associated with heating, ventilating, and air conditioning (HVAC) systems and other fluid-producing units, specifically to a water detection assembly having an electronic fluid-sensing probe with in-line positioning inside the primary drain line connected to a fluid-producing unit. In-line positioning for the electronic fluid-sensing probe is achieved via connection to an access port (also referred to herein as a cleanout unit/device) that is used for easy and fast clearing/removing of clog-causing debris from the primary drain line. The unique design of the access port's insulated housing provides a step-down fluid-collection area having an elevation lower than the bottom inside surface of the connected primary drain line segment located upstream of the access port, whether the access port is installed in a vertical or horizontal orientation. The probe is placed into a fixed position adjacent to this step-down fluid-collection area, out of the normal flow of fluid that travels from the connected fluid-producing unit, through the access port, and further down the primary drain line. It is only when a blockage occurs that the step-down fluid-collection area begins to fill with fluid, and when the amount of fluid in the step-down area reaches a threshold amount no longer considered safe (with backflow into portion of the primary drain line leading to the fluid-producing unit an imminent possibility), the rising fluid will come into contact with both of the power potentials in the present invention fluid-sensing probe, thus causing activation of a connected signal-generating unit that promptly sends an electronic signal to shut off fluid production, activate an alarm or pump, and/or provide remote notification, before rising fluid is able to move out of the step-down fluid-collection area toward the fluid-producing unit and place it at risk for damage. The unique design of the access port also allows for removal of the fluid-sensing probe, and introduction of chemicals into the drain line without any worry of retrograde backflow of the chemicals into the associated HVAC system or fluid-producing other unit. The present invention fluid-sensing probe is sealed within the access port using a longitudinal/end opening when the access port is vertically installed, and in the alternative, through a side/laterally positioned opening in the access port when it is horizontally installed. In its horizontal and vertical orientations, fluid flow through the access port occurs in opposite directions. Therefore, information markings on the outside of the access port are important to remind an installer of the needed direction of fluid flow through it to achieve a proper installation. Furthermore, the electronic fluid-sensing probe of the present invention preferably has a quick-disconnect connection to the signal-generating unit, and is without moving parts, which avoids the causes of failure common to pan-mounted water sensors having a deployable float, that include but are not limited to, inadequate leveling of the float body during installation relative to the pan wall supporting it, mounting to an insubstantial pan wall that leans-in over time, and the presence of mold, algae, and/or other interfering debris that accumulates over time on the movable float and prevents its proper deployment in response to rising fluid in the pan. When the present invention probe is in its usable position within the step-down fluid-collection area and detects fluid, the fluid completes a circuit that causes the connected signal-generating unit to send an electronic signal that shuts off fluid production, activates an alarm or pump, and/or provides remote notification to one or more locations. One of the two power potentials in the probe needed for signal generation has distal end positioning at a higher elevation than the other, and extends through its false-trigger-reducing resilient piece in a position to wait for rising fluid, without premature activation. The resilient piece has opposing ends and a cone associated with each opposing end, one of which provides a drip path to wick fluid away from the more highly elevated power potential. One of the two power potentials used may also have a circular configuration. The association of the present invention probe with a threaded cap intended for sealing a clean-out opening in the access port is also contemplated. In addition, the signal-generating unit connected to the fluid-sensing probe is preferably attached to the fluid-producing unit, a nearby wall, a secondary drain pan, or other support surface, via double-sided tape and/or fasteners.
2. Description of the Related Art
Air handling systems such as furnaces or other heating, ventilating, or air conditioning (HVAC) systems associated with a building structure typically have a primary drain pan, but may also have a secondary drain pan underneath at least a portion of the air handling unit to catch collected condensation and prevent damage the unit itself, and/or its surroundings, that otherwise might result from excess fluid collection and overflow. Furthermore, the condensation produced in a twenty-four hour period can be more than the primary or secondary drain pans can hold. This is a particularly common occurrence with some air conditioning systems. Therefore, the secondary drain pans used therewith are often mounted in a non-level orientation and connected to a drain pipe or hose that carries the collected condensate to a suitable remote location. However, in some fluid collection applications the removal of excess condensate from a secondary drain pan requires pumping. A fluid level sensing unit is also typically associated with a secondary drain pan, which is activated when the fluid level in the pan exceeds a threshold level considered safe. When that threshold is reached, the fluid level sensing unit generates a signal and sends it to a water sensor switching circuit to activate the pump. When sufficient water is removed from the drain pan by the pump to allow the water sensor to stop sending the activation signal to it, the pump becomes inactivated. In this manner, the pump is only activated when necessary to pump water out of the drain pan, thereby prolonging the life of the pump, while preventing water from overflowing the vertically-extending walls of the secondary drain pan.
Many prior art fluid level sensors in current use contain an upwardly-deployable float. One disadvantage of its use is that it may require time-consuming installation to level the float for proper and reproducible operation, or to place it at the proper height for shut-off signal activation when water depth in the associated secondary pan exceeds a threshold level considered safe to avoid damage to the fluid-producing unit and its surroundings, taking into consideration that condensate production does not immediately cease when the fluid-producing unit is shut off. If a float is not correctly oriented, deployment may be delayed or fail to occur, and the pump may not be activated in time before fluid overflows the secondary drain pan's vertically-extending walls. Such overflow generally leads to damage in the area around a secondary drain pan, which may involve a floor, walls, a ceiling, and/or fixtures associated therewith, as well as other items located nearby. In addition, false signaling may occur when floats are used, which causes pump activation when insufficient water is present, thereby damaging the pump. Thus, what is needed to provide a solution for all of the disadvantages noted above in the prior art, is a fluid level sensing unit for fluid-producing units or systems, which is durable for long-lasting and predictable use, has a reduced sensitivity to false signaling, does not require undue effort for accurate orientation, and can be relied upon to produce a signal after only a small amount fluid collects. These are all features provided by the present invention. Other desirable features and characteristics of the present invention will become apparent from the following invention description and its appended claims, as well as the accompanying drawings.